Male hypogonadism has been associated with signs and symptoms of sexual dysfunction, decreased body hair, and osteoporosis. At present, there are several androgen preparations available in the United States. These include injectable testosterone esters, which have the disadvantage of requiring injections once every 10-21 days in order to achieve adequate testosterone levels. Two oral preparations, fluoxymesterone and methyltestosterone, have the occasional complications of hepatoxicity, and thus are rarely used in this country. There are also two types of transdermal androgen patches presently available, which increase serum T level in a manner mimicking the normal diurnal variation. The patches have the disadvantage of having fixed dose increments, and some men find the "stigma" of wearing a patch unsatisfactory. In looking for an improved androgen delivery system, a testosterone 1% hydroalcoholic gel (T-gel) has been developed to allow transdermal application over broad areas of skin in a measured fashion without visible identifying patches. This method uses natural testosterone and allows a measured dose to be dispensed which then can be rubbed on to a given area of skin by the user. The gel liquefies and the alcohol rapidly evaporates leaving an unrecognizable film of testosterone on the skin which is then rapidly incorporated into the epidermal tissue. Results from the phase I testing of T-hel indicate that the daily application of 10 grams of gel (100 mg T) to the upper arm/shoulder and trunk region yields stable T levels in the high range of normal (approximately 1100 ng/dL) beginning on or about the fourth day of application. The normal range in most labs is 300-1000 ng/dL. No evidence of skin irritation was found in patients with T-gel in the phase I study. Because lower T levels than those observed in the phase I study of T-gel have been shown to alleviate the symptomatology associated with T deficiency in men, the purpose of this phase II/III trial is to compare the safety, effectiveness, and pharmacokinetics of 50 and 100 mg T/day of T-gel versus an FDA approved transdermal T-patch in hypogonadal men. Data generated from this study will be used to establish T-fel doses to be tested in a six-month, phase III study. Patients will continue or begin T-gel therapy in a follow-up study at a dose to be determined based on results of this study.